Rim-shot-sound-producing device for an electronic musical instrument

ABSTRACT

The rim shot sound of a snare drum is simulated. Upon manipulation of a key switch, a percussive sine wave having a sudden buildup and a subsequent decay is obtained. The percussive sine wave signal is introduced into a clipper circuit wherein the wave peaks in the beginning portion having great amplitude are clipped. The signal is then passed through a differentiation circuit, from which is obtained a percussive signal with harmonics richer in the beginning portion and less toward end.

United States Patent Ichikawa [451 Jan. 25, 1972 RIM-SHOT-SOUND-PRODUCING References Cited DEVICE FOR AN ELECTRONIC UNITED STATES PATENTS MUSICAL INSTRUMENT 3,141,919 7/1964 Mabuchi ..84/l.26 [72] lnventor: Kiyoshi Ichikawa, l-lamakita, Japan 3,325,578 6/1967 Park ..84/ l.0l 173] Assignee: Nippon Gakki Seizo Kabushiki Kaisha 3328506 6/1967 X Hamamatswshilamn 3,571,484 3/1971 Hirose l ..84/l.26 X [22] Filed: Mar. 18, 1971 Primary Examiner-Lewis H. Myers Assistant Examiner-Ulysses Weldon [211 App]' N 125637 Attorney-Kemon, Palmer &. Estabrook [57] ABSTRACT The rim shot sound of a snare drum is simulated. Upon 30 Foreign Applicaion priority Data manipulation of a key switch, a percussive sine wave having a sudden buildup and a subsequent decay is obtained. The per- Mar. 20, 1970 Japan ..45/23377 cussive sine wave signal is introduced into a clipper circuit wherein the wave peaks in the beginning portion having great [52] U.S. Cl. ..84/l.13, 84/ 1.26, 84/DIG. l2, li d are clipped, The ignal is then passed through a dif- 34/124 ferentiation circuit, from which is obtained a' percussive signal [51] Int. Cl. ..G10h 3/00 with harmonics richer in the beginning portion and less ow d [58] Field otSearch ..84/l.01, 1.13, 1.24, 1.26 d..

v 5 Claims, 4 Drawing Figures 'l LJfL 1 i 17 :y t ""1 12V R 5: I l v k our TR t p 1 TR2 R 11 J RIM-SHOT-SOUND-PRODUCING. DEVICEFOR AN ELECTRONIC MUSICAL INSTRUMENT BACKGROUND OF THE INVENTION .This invention relates to a rim shot sound producing device andmore particularly to a rim shot sound producingdevice for an electronic musical instrument which is capable of simulating such sounds as would beproduced on a snare drum when its rim is struck by the body ,of a stick with its tip end being in contact with the beating membrane of the drum.

In the field of electronic musical instruments, forexample, an electronic organ, there has recently been more favorably accepted a type capable of playing not only ordinary melody tonesand those of accompaniment by selective depression of a plurality of keys arranged in the'order. of musical notes but also various percussion sounds as derived from a snaredrum,

bass drum, cymbals, conga and bongos.

With respect to, for example, the snare drum included in the aforesaid percussion instruments, there are sometimes-played likesounds. This is,-so to speak, a disgrace to an electronic musical instrument which is generallyvdeemed and strongly demanded to be essentially capable of producing sounds or tones as much resembling as possible those of all natural musical instruments.

It is, therefore, the object of this inventiontoprovidea rim .shot sound producing device for an electronic'musical instrument thereby to enable said instrument more truthfullyto approach the tones or sounds playedby all natural instruments.

SUMMARY OF THEJINVENTION BRIEF DESCRIPTION OF THE DRAWING FIG. 1 represents a concrete circuit arrangement of a rim' shot soundproducing device according to an embodimentof this invention; and

FIGS. 2A to 2C illustrate concrete output waveforms from.

the main section ofthe circuit arrangement of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT It will1be noted .thatthe rim shotsoundobtainedbystriking the rim of a snare drum with the body of .a stick ischaracterized bythe waveform which tends to rise sharply atthe time of striking, gradually (but rather,fast) decay with time, contain the largest amount of harmonics (mainly includingoddorder harmonics) at the rise timeand-lose the harmonics progressively toward theend of the decay into-the form of .a substantially pure tone only consistingof the fundamental sine wave.

FIG. 1 shows a concrete circuit arrangement of a rim shot sound producing device according to an embodiment of this invention which is capable of ,playingsounds closely resembling actual rim shots. A DC source 11 (-12 volts) has ,oneof its paired terminals, for example, a positive terminal 11,, grounded. To the other negative terminal 11,, of the source 11 is connected a series resonance circuit 15 including a capacitor C, and an inductor L connected in series successively, through a normally open .key switch 12, a differentiation circuit 13 consisting of a capacitor C .and arresistorR and a rectifier 14 havinga diode D connected in the forward direction.

Under theaforementioned-arrangement, when the's'witch {12 isclosed by the manipulation of the associated key, the differentiation circuit 13 isimpressed with the negative source voltage (l2 volts). In this .case, there is obtained differentiated output voltage which sharply-risesthrough the differentiation circuit 13 at the 'momentof said voltage impression, that is, only whenthe switch 12 is closed, and then rapidly ;falls with time representing a percussive pulse --envelope. Thereaftennthe negative source'voltage is blocked by the charged capacitor C, and is not conducted to-the output side of the difi'erentiation circuit 13.

The difierentiated output voltage thus obtained from the .circuit ,13 is rectified-while passingzthrough the rectifier 14 and supplied to the series resonancecircuit 15. From the seriesresonance circuit 15, therefore, isgenerated a sine-lwave signal A, ,of a predetermined frequency havinga percussive envelope characteristic whose maximum amplitude section A, sharply (suddenly) rises atthemoment the switch l2 is closed and subsequently decays with time. In this case, the

frequency of the sine wave signal A,.is detennined bythe capacitance of the capacitor C, and the inductance of the inductor L. The envelope characteristics of the maximum amplitudesection A, are determined by the damping period of the-series resonance circuit 15, that is, the magnitude of Q thereoftas well as by the time constant derived from the product of-the capacitance of the capacitor C,- and the resistance of the resistor R constitutingthe differential circuit 13. .Needless-tosay, the aboveexplained circuitproducinga .percussivesine-wave signal may be constructed otherwise accordingtothe known circuit technique. Theresonance circuit maybe aparallel resonance circuit, too.

The present inventors experiments show thatthe rim shot sound generated from, for example, a snare .drum has a waveform which, mainly at the time-of rise, contains large amounts of odd order harmonics with respect to the fundamental frequency component of about 600 Hz. and sub- .sequentlydecays in about 20 :ms. in the form of a sound approachinga pure tone .havinga substantial sine wave. The inventors experiments have also found that where it is desired to produce sounds resembling the rim shots of a snare drum using the aforesaid .circuitarrangement, it is preferred to set the-frequency of the series resonance circuit 15 at about 600 Hz. in advance and set the decaying period thereof to about 20 ms. (said experiments further show that, to this end, the time constant of :the difierentiation circuit 15 should preferably be set atabout 4014s.). Referring to FIG. 1, a resistor R, connected in parallel with the series resonance circuit 15 is a damping resistor'provided, if required, for proper control of the decayingperiod ofithe resonance circuit 15, that is, the

magnitude of Q valuezthereof.

However, the output signal A, of FIG. 2A obtained from the series resonancecircuit 15 only consists of a substantial sine wave of about 600 :Hz. little containing harmonics from the time of rise to the extinction. Accordingly, said signal, as it is, will only produce sounds considerably different from the rim shots of the snare drum whose waveform should have the aforementionedcharacteristics.

According y, this invention consists in conducting output signal A, from the series resonance circuit 15 having the waveform of FIG. ZAsuccessively through a coupling capaciconsisting of a capacitor C, and resistor R and cascade connected to the clipper 17.

The above-mentioned circuit arrangement of this invention causes the maximum amplitude peaks of the beginning portion of output signal A, from the resonance circuit to be clipped by the clipper 17 as shown in FIG. 28 after proper amplification by the amplifier 16, so that the clipped signal is substantially flattened at the peak section to be converted from a sine to a rectangular waveform. When the clipped signal A from the clipper 17 having a waveform shown in FIG. 2B is conducted through the differentiation circuit 18, then the beginning portion whose peak point has a maximum amplitude as described above is subjected to ordinary differentiation. Only this differentiated section of the clipped signal A is made to contain proper amounts of harmonics with respect to the fundamental wave of 600 Hz. (depending on the time con stant of the differentiation circuit 18, there may be additionally performed modulation). The nonclipped portion of the output signal A, does not substantially undergo the aforementioned differentiation but is drawn out approximately in the form of a sine wave containing few harmonics, but in a smaller amplitude.

FIG. 2C shows an output waveform' A, from the differentiation circuit 18. As apparent from the foregoing description, said output waveform A, can practically produce sounds closely resembling the rim shots of the snare drum.

The transistor TR, included in the amplifier 16 of FIG. 1 is an emitter follower type so as to have a sufficiently high input impedance which would not give a loading effect to the series resonance circuit l5.

It will be apparent that generation of sounds resembling the rim shots of not only a snare but also a tenor or a bass drum can be easily effected by properly adjusting the time constant of the differentiation circuits 13 and 18 and the resonance frequency and the decaying characteristics or the magnitude of a Q value of the series resonance circuit 15.

What I claim is:

1. A rim shot sound producing device for an electronic musical instrument-comprising: a key switch, circuit means for producing a percussive sine wave signal having a sudden buildup and a subsequent decay upon manipulation of said key switch, a clipper circuit connected to said circuit means to clip the wave peaks of said percussive sine wave signal in the beginning portion thereof having great amplitudes, and a differentiation circuit to pass the clipped signal from said clipper circuit.

2. The rim shot sound producing device according to claim 1 wherein said circuit means for producing a percussive sine wave signal comprises a circuit producing a percussive pulse and a resonance circuit triggered by said percussive pulse.

3. The rim shot sound producing device according to claim 1 wherein said resonance circuit consists of a capacitor and an inductor.

4. The rim shot sound producing device according to claim 

1. A rim-shot-sound-producing device for an electronic musical instrument comprising: a key switch, circuit means for producing a percussive sine wave signal having a sudden buildup and a subsequent decay upon manipulation of said key switch, a clipper circuit connected to said circuit means to clip the wave peaks of said percussive sine wave signal in the beginning portion thereof having great amplitudes, and a differentiation circuit to pass the clipped signal from said clipper circuit.
 2. The rim shot sound producing device according to claim 1 wherein said circuit means for producing a percussive sine wave signal comprises a circuit producing a percussive pulse and a resonance circuit triggered by said percussive pulse.
 3. The rim shot sound producing device according to claim 1 wherein said resonance circuit consists of a capacitor and an inductor.
 4. The rim shot sound producing device according to claim 3 wherein said resonance circuit further includes a damping resistor connected therein.
 5. The rim shot sound producing device according to claim 1 wherein said clipper circuit consists of a saturation amplifier so designed as to clip at a substantially half voltage level of the maximum amplitude envelope portions. 